Aug. 30, 2011 (Paris) -- Taking the blood thinner Plavix for six months after receiving a stent may be safer and just as effective as two years of treatment, a new study suggests.

The standard recommendation is typically at least 12 months of Plavix. But the study found that six months of treatment was enough to prevent rare but deadly complications, says researcher Marco Valgimigli, MD, of the University Hospital of Ferrara, in Italy.

Stents are tiny mesh tubes used to prop open an artery after a balloon angioplasty procedure opens the clogged artery.

As blood flows through the stent, clots can develop. The clots can lodge in an artery, causing a heart attack.

That's why people who get stents get blood-thinning treatment with a combination of aspirin and Plavix or similar drugs.

But no one really knows how long patients should stay on Plavix. Current guidelines call for at least one year of treatment, but "there's still a high degree of uncertainty," Valgimigli tells WebMD.

Shorter Plavix Treatment Safer, Just as Effective

The new study, dubbed PRODIGY, involved nearly 2,000 patients who received either a bare-metal stent or a newer drug-coated stent. They were divided into two groups: One got Plavix and aspirin for six months, and the other for two years.

The results were presented here at the European Society of Cardiology Congress 2011.

About 10% of people in both groups had a heart attack or stroke or died, showing "six months may be enough," Valgimigli says.

The reason for the shorter duration of Plavix use comes down to the finding that patients getting two years of treatment were about twice as likely to have a serious bleed: 7.4% vs. 3.5% of those on six months of therapy.

Further analysis showed that the results held true regardless of age, sex, type of stent, and severity of disease. However, "we will dig further into these subgroups," Valgimigli says.

One study isn't enough to change guidelines. But two other recent studies have shown similar results, according to Valgimigli.

American Heart Association President Gordon Tomaselli, MD, director of cardiology at Johns Hopkins Medical Institutions, tells WebMD that the studies are likely to prompt the organization to revisit guidelines on the optimal duration of Plavix treatment for patients with stents.

Adnan Kastrati, MD, professor of cardiology at the Technical University of Munich, in Germany, was charged with putting the findings into perspective for meeting attendees.

"Although we are still waiting for the results of a larger trial on the optimal duration of [Plavix] therapy after stenting, the PRODIGY trial represents one more victory against the greatest enemy of the drug-coated stent: the wrongly assumed need for endless treatment," Kastrati said.

The findings also have major implications for cost savings. Plavix typically costs $4 to $6 a day, although a generic version due out soon is expected to be cheaper.

What about aspirin? Unless patients are at high risk of bleeding complications, "I typically tell my patients to stay on aspirin forever as they have underlying coronary artery disease" that led to the stent procedure in the first place, Tomaselli tells WebMD.